This disclosure relates generally to guidewires, and more particularly, to a system and method of integrating trackable elements into the guidewires for tracking the guidewires within vasculature of a patient.
A guidewire typically includes a flexible wire positioned in an organ, vessel, or duct of a patient for the purpose of directing passage of a larger device threaded over or along the length of the guidewire to a desired location in the vasculature of the patient. A wide variety of guidewires have been developed for various applications including medical applications, such as, but not limited to, coronary angioplasty. Also, endovascular interventions are rapidly advancing as a viable alternative for invasive vascular surgery. During these interventions, a guidewire is generally inserted into a region of a patient, such as the groin region, and the guidewire is then advanced to a desired location, typically under fluoroscopic guidance. Accurate positioning of the guidewire with respect to the vasculature is a prerequisite for a successful procedure. Furthermore, during neuro-interventions, positioning the guidewire accurately is difficult due to the complexity of the vasculature and narrowness of the blood vessels, thereby resulting in an increase of intervention time and exposure to radiation.
Recently, the guidewires have been known to include one or more tracking elements, such as but not limited to a sensing device, such as a microsensor. Surgical navigation systems may then be employed to track the location of the tip of the guidewire by tracking a location of the integrated microsensor, for example. A clinician may use the location information associated with the guidewire to efficiently navigate the guidewire to the desired location.
Numerous guidewires having integrated sensors have been developed. Unfortunately, incorporation of trackable sensors of high signal strength into devices of the sizes provided by typical guidewires having a diameter of less than 1 mm is an onerous task. Additionally, these trackable sensors may require a shielded type of electrical connection (e.g., coax or twisted pair) with the surgical navigation tracking system to reduce the introduction of noise into the electromagnetic signal. However, the introduction of the additional electrical connection disadvantageously results in the wires occupying precious real estate in the guidewire and hence reducing the real estate available for other connections. Furthermore, additional structural elements may be required to provide the desirable strength to the guidewire.
Moreover, one of the biggest challenges to the design of trackable guidewires is a method of attaching a trackable element to a distal end of the guidewire. The trackable element may include a microcoil, for example. One of the challenges with attaching the trackable element to the guidewire includes an electrical challenge. As will be appreciated, electrically, it may be desirable to have at least two electrically isolated conductors running from a start lead and a finish lead of the microcoil at the distal end of the guidewire, all the way down the length of the guidewire to a connection at a proximal end of the guidewire. These conductors may be used to energize a sensor coil, if it is a transmitter, or to pick up the induced signal if it is a receiver.
Also, a second challenge in attaching the trackable element to the distal tip of the guidewire may include a mechanical challenge. The leads running the length of the guidewire occupy precious real estate in the guidewire. As will be appreciated, there exist numerous applications for which it may be advantageous to maximize the amount of room available inside the guidewire. The room within the guidewire may be rendered hollow. Alternatively, a lumen may be created in the guidewire. Furthermore, it may be desirable to make the room within the guidewire available for other internal components of the guidewire, where the internal components may be configured to enhance steerability of the guidewire and/or to tailor flexibility of the guidewire. In addition, mechanically, it may also be desirable to imbue the guidewire with certain properties like flexibility, “pushability” (column strength) and torquability, which may vary according to the application for which the guidewire is being used.
It may therefore be desirable to develop a robust guidewire for systematically navigating the guidewire to the desired location. In particular, there is a need for a design of a guidewire that is configured to simultaneously provide electrical conductivity and mechanical strength to the guidewire. There also exists a need for efficiently coupling the trackable element to the guidewire with minimal impact on the performance of the guidewire during clinical applications.